The remains of Leonardo da Vinci are to be exhumed by a group of scientists who plan to reconstruct his face to discover whether his famed masterpiece, the Mona Lisa, is a self-portrait in disguise.  A team of art historians and scientists from Italy's National Committee for Cultural Heritage, has requested that his tomb at Amboise Castle in the Loire valley be opened. Anthropologist Giorgio Gruppioni, hopes the project will throw new light